Disconnect signal board, independent maintenance power deflection plate, observe + B switch power supply output light is not bright. Check + B voltage current limiting resistor E994 insurance already open, after the preliminary confirmation + B load no short circuit phenomenon change E994, access signal board, burn E994 boot again. Burn E994 analysis has two situations: (1) + B abnormal voltage rise; Second, the line circuit flow phenomenon. + B terminal voltage is 70 v, this machine is in standby state, determining basic normal power supply + B, focusing on line of circuit. Test manager Q777 normal, T702 output transformer fault is still a new line. Will last 3 guns high pressure from the line of the output transformer, switch on normal. High pressure one by one in three shots, when access to blue gun, boot and burn R994, confirmed the blue gun internal short circuit phenomenon, caused by burn E994 line current increases. Change the blue gun projection tube, adjust the machine to normal after convergence.Ah9service manual download site